System for cooling a heated juice by partial low-pressure evaporation

ABSTRACT

A system for cooling a heated juice by partial low-pressure evaporation, said juice comprising a charged liquid, preferably juice from a harvested crop, said system comprising a vat in which the juice is subjected to various pressure reductions, said vat ( 4 ) comprising at least two compartments( 5,6 ) which communicate with each other by means of a pulsed-effect valve, said juice being subjected to two different decreasing pressure reductions in said compartments, each compartment being connected to a condenser ( 19,25 ) which can condense the vapor produced by the pressure reduction. The condensers are serially mounted or parallel mounted and connected to a common vacuum pump ( 34 ) by means of at least one control valve ( 18 ) which can permanently adjust the pressure in each condenser to a value which is lower than the saturating vapor pressure corresponding to the temperature of the vapor created in each of the condensers. The invention is characterized in that the compartments ( 5,6 ) of the vat are superposed and communicate with each other therein by means of an opening ( 8 ) through which the juice passes, said opening being closed either fully or partially by a variably positioned shutter element, creating a pulsed effect in order to remove the solid particles contained in the juice.

[0001] The present invention relates to an installation, allowing thecontrolled cooling, in carefully determined conditions, of a liquidjuice, in particular charged with berries from an agricultural harvest,and applies more particularly although not exclusively to the treatmentof juice from a harvested crop during the process of making it intowine.

[0002] It is known that the qualities of a wine, in particular itsorganoleptic properties, depend on its concentration and on itsproportions in a certain number of flavouring matters, or even colouringagents, in particular of the aromatic type, precursors of aromas,tannins, pigments, anthocyanin compounds, and also various other more orless volatile compounds such as polyphenols and polysaccharides, whichturn out to be essentially contained in the skin of grapes.

[0003] The French patent published under No. 2 712 147 describes aprocess for carrying out an initial treatment of a juice from aharvested crop with a view to extracting these compounds moreeffectively, by a mechanical disorganization of the cells in the skin ofthe grapes, encouraging their release and allowing the subsequent stagesof making wine from the harvested juice to be optimized.

[0004] In particular this process consists, after having heated thejuice which is to be treated to a temperature comprised between 80 and95° C. for a few minutes by direct heating or by means of an exchangerto already develop certain organoleptic properties of this juice in away which in itself is known in the prior art, of subjecting the thusheated liquid, in a closed vat, to a sudden drop in pressure whichbrings about its cooling down as a whole and at the same time causes apartial vaporization of the water contained in this juice, the vapourproduced being then condensed and, as a general rule, returned to thecooled juice to satisfy the imposed regulations.

[0005] According to the patent cited, this pressure reduction underreduced pressure disorganizes the tissues of the grapes and breaks downthe structure of the cells of its skin, while releasing a substantialquantity of precisely those compounds which are desired to be recovered,while avoiding their elimination with the solid residues which come fromthe pulp of the juice.

[0006] The thus treated juice, which comes out of the vat at relativelylow temperature, in this case below 35° C., is then subjected to otherstandard stages of maceration, of more or less extended vat time, i.e.storage in the vat to allow the development of certain enzymatic orother reactions, before the fermentation begins, leading to the finaldevelopment of the wine.

[0007] The process proposed in this previous patent thus allows a winemore charged with tannins to be obtained, having more structure and alsoa greater suppleness, and which is less sensitive to chemicalalterations, all in all with a greatly improved storage time.

[0008] But if the stage of pre-heating followed by a sudden cooling bypressure reduction under reduced pressure has, according to the citedpatent, incontestable advantages, it may be suspected that theentrainment of the aromas and other substances from the breaking down ofthe structure of the grape skins with the produced vapours is notoptimal. In fact, the vapour produced by pressure reduction of theheated juice is fundamentally made up of water vapour so that thevolatile or undesirable compounds remain contained in the cooled liquidpart. This precisely means that the temperature of the juice from aharvested crop is lowered rapidly and significantly.

[0009] In fact, if the temperature were to remain above the limit of 30to 35° C., fermentation of the juice would begin immediately underaccelerated conditions, with harmful and irremediable consequences forthe following stages of the winemaking process.

[0010] In consequence, in the process according to the previously citedpatent, the cooling of the pre-heated juice constitutes a determiningfactor when it is seen in an overall perspective of winemaking.

[0011] However, the implementation of this process, which is moreoverexclusively claimed in the cited patent in that it shows how to obtain ajuice where the phenolic compounds and/or the precursors of aromas arepresent in a quantity which is 50% higher than that which is observedwith baths which are treated by a standard process, requires, in orderto obtain an adequate condensation of the vapour produced at the giventemperature, because of the pressure reduction of the juice to lowpressure, a condenser where the exchange surfaces are large and theflow-rate of the cooling fluid, made up of water, is very high.

[0012] From then on, the installation produced, where the pressurereduction of the juice heated at low pressure is obtained in a singlevat of large dimensions, is not suited for localized treatment, inparticular close to the site of each harvest, where the flow-rate of theavailable water is necessarily reduced, the temperature of this water atthe site moreover not always being suited to the required coolingconditions.

[0013] The American patent published under No. 1 799 478 describes anevaporation and concentration device for a liquid heated and chargedwith solid matter comprising a vat which is continuously supplied withthis liquid. Here, the vat comprises three separate compartments, whichare superposed and communicating with each other, where the liquid issubjected to successive pressure reductions at decreasing pressures,each compartment being connected to a condenser.

[0014] However, the pressure reductions produced by this device are notsufficient, and the output of the installation as well as its large bulkmake it not very efficient.

[0015] A subject of the present invention is an installation where thecooling of the heated juice by sudden pressure reduction under reducedpressure is carried out so that the flow rate of water required tocondense the vapour produced is appreciably lower, the size of thecondensers being smaller, the entrainment of the aromatic compounds andcolouring agents in the vapour being more limited moreover, allowingessentially the juice itself to be treated, without involving thecondensates subsequently returned to the latter.

[0016] Still more particularly an aim of the invention is to permanentlycontrol the conditions in which the cooling of the heated juice occurs,with the possibility of adjusting at any time the values of thepressures applied to ensure the condensation of the vapour, according tothe required operating conditions.

[0017] To this end, the installation considered, for carrying out thecooling by evaporation of a juice heated to an initial temperature ofthe order of 65 to 90° C., constituted by a charged liquid andpreferably juice from a harvested crop, comprising a vat supplied withcontinuous flow of this juice, which is subjected in this vat to severalpressure reductions by sudden reduction of its pressure with theproduction of saturated vapour at the lower temperature created as aresult of this reduction, said vat comprising at least two separate butsuperposed compartments, communicating with each other, respectively afirst upper compartment and a second lower compartment, where the juiceis subjected to these successive pressure reductions to two differentand decreasing pressures, lower than that of the juice when it entersthe vat, each compartment being connected to a condenser, capable ofcondensing the vapour produced by the pressure reduction, thesecondensers being serially mounted or parallel mounted and connected to acommon vacuum pump by means of at least one control valve which canpermanently adjust the pressure in each condenser to a value which islower than the saturation vapour pressure corresponding to thetemperature of the vapour created in each of these condensers ischaracterized in that the compartments of the vat are superposed andcommunicate with each other therein, by means of an opening throughwhich the juice passes, which is closed either fully or partially by avariably positioned shutter element, creating a pulsed effect in orderto remove the solid particles contained in the juice, this shutterelement being self regulating as a function of the conditions of use ofthe installation

[0018] As a result of putting the juice under reduced pressure in eachof the successive compartments of the vat, there is produced a partialvaporization of the liquid phase contained in this juice and a loweringof the temperature within the mass to a value which depends only on thispressure.

[0019] However, because of the division of the vat into at least twoseparate and communicating compartments, where the pressures areadjusted by the vacuum pump and the control valves linked to thecondensers to values that are different and decreasing from one to thenext, the droplets produced in each of these condensers are of greatersize, which allows them to be separated more easily and above allensures that the majority of them fall back under the effect of gravityto the lower end of each compartment, and are not carried towards thecorresponding condenser.

[0020] In each compartment, the mass flow rate of vapour produced islower and, for the same entrainment speed, the difference between thetemperature of the heated juice upon entry and the cooling temperatureobtained, thus imposes the dimensions of the compartment of thecorresponding vat, so that, when this difference is lesser, so are thesedimensions.

[0021] As a result there is also a limitation to the superheating of thevapour, which makes it easier to condense it.

[0022] Moreover, the possibility of producing a vat of smaller sizeallows a more convenient transportation of it from one production siteto another, unlike a unit with a single vat, with dimensions which arenecessarily very large in order to allow the continuous treatment of asignificant flow rate of juice.

[0023] Finally, as a consequence of this reduced temperature differencein each compartment the exchange surface in the linked condenser canalso be smaller, requiring a more limited flow rate of cooling water,better compatible with the usual possibilities of each operation, inparticular the water system available at the site.

[0024] Preferably, the shutter element is constituted by a conicalshaped valve cooperating with a seat of the same profile installed in adividing wall between the two compartments, in the shape of a funnel,this valve being integral with a float which is able to lift it from itsseat to a distance which is a function of the quantity of liquid juicerecovered in the bottom of the first compartment and to adjust theopening to the second compartment, which is arranged beneath the first.

[0025] The valve advantageously has a peripheral edge rounded at the topto allow it to be supported on its conical seat in the dividing wall andto absorb possible misalignments of it due to the turbulence of theliquid juice in the first compartment.

[0026] According to another distinctive characteristic, the valve isequipped with, at its base opposite its peripheral edge in its upperpart, a stop plate, in this valve's maximum raised position.

[0027] Preferably also, the float moreover comprises a cover forprotection from the liquid, held by the internal surface of the firstcompartment and which extends transversely above and at a distance fromthe float.

[0028] Advantageously, the protective cover of the float comprisesvertical rods for guiding its movements in the first compartment.

[0029] According to yet another characteristic, the vat communicates inthe upper compartment with a first condenser by means of adroplet-catching device to separate the produced vapours which arecreated in this condenser on the one hand, the drops and the solidparticles charging the juice to be treated on the other hand.Preferably, this droplet-catching device is arranged in the upper partof this first compartment, to the right of a conduit linked with thecondenser.

[0030] According to another aspect of the invention, the two condensers,linked respectively to the two compartments of the vat at differentpressures, are arranged serially or in parallel by means of linkingtubes, equipped with stop valves.

[0031] The condenser linked to the first compartment comprises upstreama first valve to create an adjustable loss of charge, which is able toadjust the pressure of the vapour in this condenser in order to allowits condensation.

[0032] According to yet another characteristic of the invention, thecommon vacuum pump, connected to the condensers, is a liquid ring pump,which is able to maintain the value of the pressure in these condensersat a value which is always lower than the saturation vapour pressure inthe two compartments of the vat, so as to permanently produce thecondensation of this vapour, no matter what its flow rate on entry intothese condensers.

[0033] Advantageously, the vacuum pump comprises an ejector device,which can further reduce its pressure upstream.

[0034] Finally, the installation preferably comprises, at the outletfrom the second compartment, in the lower part of the vat, a pump forextraction of the cooled juice, which can also extract the condensatesfrom a container for recovering these, arranged at the outlet of the twocondensers.

[0035] Using all of these characteristics and especially employing twosuperposed and communicating compartments, arranged inside the vat,while reducing the overall volume of the installation, allows thedistribution of the pressures in each of these compartments to beuncoupled and managed, independently of the temperature of the juiceupon leaving these. In this way, the breaking down of the structure ofthe berries and more generally of the components of the treated juicecan be controlled independently of this temperature.

[0036] The invention moreover allows the cooled down liquid to beconcentrated, while reducing the flow rate of the cooling waternecessary and/or the temperature levels.

[0037] Other characteristics of an installation for cooling a liquidjuice, made according to the invention, are also set out in thedescription which follows of an embodiment, given by way of example andwhich is not limiting, with reference to the attached drawings in which:

[0038]FIG. 1 is a diagram schematically illustrating all of theinstallation with its vat with two compartments and the differentcontrol and adjustment elements which associated with it.

[0039]FIG. 2 is a schematic view in axial section of an embodiment ofthe vat considered.

[0040]FIG. 3 is a cross-section view, on a larger scale, illustratingthe lower part of the first compartment of the vat with the shutterelement of the opening between the two compartments.

[0041]FIG. 4 illustrates, on an even larger scale, the structure of theshutter element of FIG. 3.

[0042]FIG. 5 is a view of a detail of the shutter element.

[0043] In FIG. 1, reference 1 refers to a feed tank of the installationconsidered with a charged liquid juice, preferably constituted by agrape juice, this liquid being taken to a temperature comprised betweenapproximately 65 and 90°, using means which are not represented, bydirect or indirect heating, the heating conditions of the liquid juice,in particular by passing through a heat exchanger or by any otherstandard process, not directly being a part of the invention

[0044] The heated juice on leaving the tank 1 is taken via a pipe 2equipped with an inlet valve 3 to the upper part of a vat 4, producedaccording to the invention and which comprises in particular, in theembodiment being considered, two superposed compartments, respectivelythe upper compartment 5 and the lower compartment 6, these compartmentsbeing appreciably separated in the middle section of the vat by adividing wall 7, preferably in the shape of a funnel and which comprisesin its centre an opening 8 allowing communication to be establishedbetween the two compartments.

[0045] The opening 8 can be shut or conversely opened as a function ofthe relative position with respect to that of a shutter element 9, theproduction details of which are specified later, this shutter elementbeing connected by a connecting rod 10 to a float 11 which allows thevertical variation of the position of the shutter element depending onthe level 12 of the liquid collected at the base of the firstcompartment 5 against and above the wall 7.

[0046] The lower part of the vat 4 comprises a bottom 13, preferablyalso in shape of a funnel, which communicates through a conduit 14 witha container 15 where the liquid product coming out of the vat iscollected, this container being connected, by means of a flow meter 16or another measuring device equivalent to an evacuation pump (notrepresented), which returns this product towards other installationswhere it is subjected to an complementary treatment which is notdirectly related to the precise subject of the invention.

[0047] In particular, when the treated juice is a juice from a harvestedcrop, it can thus be conveyed to additional standard installations, inwhich the stages necessary for the wine-making process are carried out.

[0048] The first compartment 5 of the vat 4, situated in the uppersection of the latter, comprises a conduit 17 equipped with a firstvalve 18 arranged upstream of a first vapour condenser 19, the condensedvapour produced being collected in an outlet conduit 20 and returned byevacuation tubes 21 into the liquid flow which comes out of the vat 4through the container 15.

[0049] The condenser 19, called a high pressure condenser for thereasons which are set out below, as opposed to a similar condensercalled a low pressure condenser, comprises pipes, respectively for inlet22 and for evacuation 23, of an appropriate cooling liquid, usuallywater in continuous circulation.

[0050] The lower compartment 6 of the vat 4, arranged in the latterunder the first compartment 5, also comprises an outlet conduit 24,which connects this compartment to a second condenser 25, called a lowpressure condenser, the latter comprising, like the high pressurecondenser 19, pipes 26 and 27 for inlet and for evacuation of anappropriate cooling liquid.

[0051] The condensed vapour which is evacuated from the condenser 25, iscollected in an outlet pipe 28 and is also returned by the evacuationtubes 21 to the flow of liquid juice which leaves the container 15.

[0052] The two condensers 19 and 25, respectively linked to compartments5 and 6 of the vat 4, can, depending on the case, be arranged seriallyor in parallel, thanks to valves 29, 30 or 31, respectively open orclosed depending on the chosen assembly.

[0053] Moreover, the common outlet of the two condensers is connected bya conduit 32 to a flow meter 33 which is itself connected to a vacuumpump 34, preferably a liquid ring pump and advantageously by means of anejector 35. Connection pieces 36 are provided at various points of thecircuit for the installation of thermocouples, allowing the value of thetemperatures at each of these points to be measured.

[0054] The operation of the installation described above consistsessentially of subjecting the heated liquid juice, which runs into one,then into the other of each of the two compartments 5 and 6 of the vat4, at a pressure very appreciably lower than that at which it is atbefore its entry into the vat, i.e. at atmospheric pressure, thepressure in the first upper compartment 5 being for example of the orderof 100 mbar, while it is lowered to 30 mbar in the lower compartment 6.

[0055] Thus, the heated liquid juice, introduced into the lower sectionof the first compartment 5, will here be subjected to a sudden pressurereduction allowing it to be suddenly and partly vaporized, while takingit to a lower temperature, equal to that which corresponds to thesaturation vapour pressure thus created in this compartment.

[0056] The vapour created, called high pressure vapour as opposed tothat obtained subsequently in the second compartment 6, is collectedthrough the conduit 17 and the valve 18 in the first condenser 19, wherethe cooling conditions and the loss of charge created by this valve, incombination with the effect of the vacuum pump 34, if appropriateassociated with the ejector 35, allowing the complete condensation ofthis vapour and its possible return to the product coming out of thevat, as has already been indicated.

[0057] Advantageously, the vapours created by the pressure reduction ofthe heated liquid juice admitted into the first compartment 5, passthrough a droplet catcher or separator (not represented), before beingtaken up by the conduit 17 and sent to the high pressure condenser 19,this conduit being connected to the compartment, at the upper section ofthe latter.

[0058] The pressure reduction of the heated juice moreover causes,inside the compartment 5, the formation of droplets of liquid which fallunder the effect of gravity in this compartment and collect on thedividing wall 7, in the shape of a funnel, separating it from the secondcompartment 6.

[0059] The opening 8 provided in this wall is normally blocked by theshutter element 9, until the float 11 integral with this shutterelement, carried by the level 12 of the liquid in the bottom of thefirst compartment 5, is raised from its seat and thus opens thecommunication between the compartments 5 and 6, before it returns to itsinitial position and is raised again, the pulsed effect created by thisshutter element in particular allowing the effective evacuation of thesolid particles contained in the juice.

[0060] The liquid already cooled following the pressure reductioncreated in the upper compartment 5, is now subjected in the secondcompartment to another pressure reduction where the vapour produced isthis time collected under the same conditions as previously by theso-called low pressure condenser 25, the temperature in the secondcompartment being again reduced as a function of the operatingconditions created and in particular of the saturation vapour pressurein this compartment.

[0061] The liquid fraction collected at the base of the vat 4 in thebottom of the second compartment 6 is thus brought back to a temperatureconsiderably lower than that of the juice in the feed tank 1, inparticular passing from approximately 80 to 30° C., the two successivepressure reductions produced allowing a satisfactory breakdown of thestructure of the grapes and the obtaining of a final product in whichthe content of organoleptic components is very noticeably improved.

[0062] As already indicated, it is thus ascertained that thisarrangement with two compartments superposed in the vat, allows thedistribution of the pressures inside each of these compartments to beuncoupled and managed, the breakdown of the structure of the solidelements contained in the juice being able to be controlledindependently of its outlet temperature.

[0063]FIG. 2 illustrates a preferred embodiment of a vat 4 according tothe invention comprising two superposed compartments 5 and 6,respectively associated with two condensers of the produced vapour, oneof them 19, connected to the upper compartment 5, being called a highpressure condenser, while the other, connected to the lower compartment6, is called a low pressure condenser, the vapours obtained by pressurereduction of the heated liquid juice in these successive compartmentsbeing at different pressures, simultaneously taking the liquid totemperatures which are distinct and lower from one to the next.

[0064] FIGS. 3 to 5 illustrate a particular embodiment of the shutterelement 9 of the float 11 linked by the rod 10.

[0065] This shutter element 9 advantageously has a conical profile, withan upper lip 37 having a rounded peripheral edge 38, so as to come tobear against the dividing wall 7, even in the case of a slightmisalignment of the shutter element, when the latter is not raised fromits seat 39, to the same level as the opening 8, between the superposedcompartments 5 and 6.

[0066] The shutter element 9 preferably comprises a blind hole 40 intowhich is inserted a rod 41 which ends in a transversal plate 42, whichcan abut against a support 43 provided under the dividing wall 7, thissupport thus limiting the maximum raising of the shutter element 9 byits float 11, as the level of the liquid collected in the bottom of thefirst compartment 5 increases.

[0067] Advantageously, during the successive upward and downwardmovements of the float 11 under the effect of the variations of thelevel 12 of the liquid in this compartment 5, with the pulsed effectwhich results for the valve 9, this float is guided by means of verticalrods 44, held by a cover 45 fixed by lugs 46 against the internal wallof the compartment, as illustrated in FIG. 3.

[0068] Thus an installation is produced which allows the cooling of acharged liquid and in particular a juice from a harvested crop, in a waywhich has numerous advantages, this cooling, for a given liquid flow atthe inlet, being ensured so that it allows, in a way that is in itselfknown, effective mechanical disorganization of the cells of the grapeskins with the advantages which result from this to optimize thequalities of this juice to subsequently make it into wine.

[0069] In particular, the production of the pressure reduction vat in atleast two separate compartments allows the successive temperature levelsto which the juice is taken to be stepped, by obtaining in eachcompartment a larger liquid drop size, in particular limiting aentrainment of these with the vapour, which facilitates the operation ofthe condensers and improves their efficiency.

[0070] The dimensions of these condensers can moreover be reduced; inaddition, the flow rates of the cooling liquid taken to these condenserscan be lower and/or the temperature of the liquid higher, so that theoperating conditions, and in particular the pressure created by thecontrol valve and the vacuum pump in the compartments of the vat inorder to reach the desired temperatures following the pressurereductions and the evaporation of the juice in the two successivecompartments, are better suited to a transportable installation and areless costly, able to operate on site, directly where the harvesting iscarried out.

[0071] Of course, it goes without saying that the invention is notlimited to the embodiment more specifically described above withreference to the attached drawings; on the contrary it encompasses allthe variants.

1- Installation for cooling by evaporation of a juice heated to aninitial temperature of the order of 80 to 90° C., constituted by acharged liquid and preferably by a juice from a harvested crop,comprising a vat supplied with a continuous flow of this juice, which issubjected in this vat to several successive pressure reductions bysudden reduction of its pressure with the production of saturated vapourat the lower temperature created as a result of this pressure reduction,said vat comprising at least two compartments, separate but superposed,communicating with each other, respectively a first upper compartment(5) and a second lower compartment (6), where the juice is subjected tothese successive pressure reductions to two different and decreasingpressures, lower than that of the juice at its entry into the vat, eachcompartment being connected to a condenser (19, 25), which is able tocondense the vapour produced by the pressure reduction, these condensersbeing serially mounted or parallel mounted and connected to a commonvacuum pump (34) by means of at least one control valve (18) capable ofpermanently adjusting the pressure in each condenser to a value which islower than the saturation vapour pressure corresponding to thetemperature of the vapour created in each of these condensers,characterized in that the compartments (5, 6) of the vat are superposedand, communicate with each other, in the latter, by an opening (8)through which the juice passes, closed either fully or partially by avariably positioned shutter element, creating a pulsed effect in orderto remove the solid particles contained in the juice. 2- Installationaccording to claim 1, characterized in that the shutter element isconstituted by a conical shaped shutter element (9) cooperating with aseat with the same profile arranged in a dividing wall (7) of the twocompartments (5, 6) in the shape of a funnel, this shutter element beingintegral with a float (11) which is able to raise it from its seat to adistance which is a function of the quantity of liquid juice collectedin the bottom of the first compartment (5), and to adjust the opening tothe second compartment, arranged under the first. 3- Installationaccording to claim 2, characterized in that the shutter element (9) hasa rounded peripheral edge (38). 4- Installation according to one ofclaims 3 or 4, characterized in that the shutter element (9) is equippedat its base, opposite its peripheral edge (38) with a stop plate in themaximum raised position of this shutter element. 5- Installationaccording to any one of claims 2 to 4, characterized in that the float(11) comprises a cover (45) to protect it against the liquid, carried bythe internal surface of the first compartment (5) and which extendstransversely over and at a distance from the float. 6- Installationaccording to claim 5, characterized in that the protective cover (45) ofthe float (11) comprises vertical rods (44) for guiding its movements inthe first compartment (5). 7- Installation according to any one ofclaims 1 to 6, characterized in that the vat (4) communicates in theupper compartment (5) with a first condenser (19) by means of adroplet-catching device for separating the produced vapours created inthis condenser on the one hand, the drops and the solid particlescharging the juice to be treated on the other hand. 8- Installationaccording to claim 7, characterized in that the droplet-catching deviceis arranged in the upper section of the compartment (5), to the right ofa conduit (17) connected to the condenser (19). 9- Installationaccording to any one of claims 1 to 8, characterized in that the twocondensers (19, 25), connected respectively to the two compartments (5,6) of the vat (4) at different pressures, are arranged serially or inparallel by means of connecting tubes, equipped with stop valves (29,30, 31). 10- Installation according to any one of claims 1 to 9,characterized in that the condenser (19) connected to the uppercompartment (5) comprises a valve (18) upstream to create an adjustableloss of charge, which can adjust the pressure of the vapour in thiscondenser. 11- Installation according to any one of claims 1 to 10,characterized in that the common vacuum pump (34), connected to thecondensers (19, 25), is a liquid ring pump. 12- Installation accordingto claim 11, characterized in that the vacuum pump (34) comprises anejector device (35). 13- Installation according to any one of claims 1to 12, characterized in that it comprises, at the outlet to the secondcompartment (6), in the lower part of the vat (4), a pump for extractionof the cooled juice.